Assembly, shock absorber, and method for manufacturing assembly

Abstract

This assembly includes a plurality of stacked circular members, and a fixing pin that is disposed inside each of the circular members to arrange and integrate each of the circular members in an axial direction thereof. The fixing pin includes a shaft portion extending in the axial direction, a flange portion extending radially outward from one end side of the shaft portion, a recessed portion that is provided on an end face of the shaft portion on the other side and has a non-circular cross-section orthogonal to the axial direction, and one or a plurality of protruding portions that are provided on an outer circumferential portion of the shaft portion on the other end side and protrude radially outward from an inner circumferential surface of each of the circular members.

The invention claimed is: 
     
       1. A method for manufacturing an assembly in which a fixing pin is disposed inside a plurality of stacked circular members to arrange and integrate the circular members in an axial direction thereof, comprising:
 a shaft portion insertion step of inserting a shaft portion of the fixing pin into the plurality of circular members, the fixing pin including the shaft portion extending in the axial direction and a flange portion extending radially outward from one end side of the shaft portion; and 
 an integration step of inserting a non-circular punch into a non-circular recessed portion provided on an end face of the shaft portion on the other end side to rotate the punch, having the maximum diameter larger than the minimum diameter of the non-circular recessed portion, 
 plastically deforming an outer circumferential portion of the shaft portion on the other end side to protrude radially outward from an inner circumferential surface of the circular members, and integrating the plurality of circular members with the fixing pin. 
 
     
     
       2. The method for manufacturing an assembly according to  claim 1 , wherein in the integration step, an axial force is applied to the plurality of circular members in the axial direction before the punch is rotated. 
     
     
       3. The method for manufacturing an assembly according to  claim 1 , wherein, in the integration step, the punch is rotated in a state in which a tip face thereof on an insertion side into the recessed portion is located on the same plane as an end face of a circular member on a side opposite to the flange portion, the circular member being provided on a side most opposite to the flange portion among the plurality of circular members, or on a side opposite to the flange portion and closer thereto than the end face. 
     
     
       4. The method for manufacturing an assembly according to  claim 1 , further comprising, before the integration step, a restriction step of holding an outer circumferential surface of the flange portion formed in a non-circular shape and restricting movement of the fixing pin in a rotational direction thereof.